how-to-install-archlinux-from-scratch.md

How to install ArchLinux on uConsole/CM3 from scratch

DRAFT

Now I recommend to use the scripts at PotatoMania/uconsole-cm3-arch-image-builder to build the OS image.

It looks like there's a more detailed guide at Autianic/clockworkpi-linux. It tells how to build the packages and how to make the partitions. The exception is that CM3 can only boot from a fat partition on a MBR partition table, with a proprietary bootloader. So no u-boot related stuff is necessary.

A Linux-based host computer(a VM is fine) is required for this guide. In best case, an ArchLinux host. If OS installation is not preferred/available, live CDs can be used.

This guide assumes that a ArchLinux host is used. Please make necessary changes when operating with other distros.

Create partitions

Here we choose MBR partition scheme. If GPT(GUID partition Table) is preferred, please refer make partitions gpt.

Any tool can be used. The goals are:

• Create an empty MBR partition table
• Create a FAT32 primary partition
• Create EXT4 primary partition

If you've already done this, skip to next section.

Here fdisk is used(/dev/sdx is the SD card):

> sudo fdisk /dev/sdx
[sudo] password for hyx:

Welcome to fdisk (util-linux 2.39.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help): o
Created a new DOS (MBR) disklabel with disk identifier 0xf12e4306.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1):
First sector (2048-62357503, default 2048):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-62357503, default 62357503): +512M

Created a new partition 1 of type 'Linux' and of size 512 MiB.

Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p):

Using default response p.
Partition number (2-4, default 2):
First sector (1050624-62357503, default 1050624):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (1050624-62357503, default 62357503):

Created a new partition 2 of type 'Linux' and of size 29.2 GiB.

Command (m for help): t
Partition number (1,2, default 2): 1
Hex code or alias (type L to list all): 0c

Changed type of partition 'Linux' to 'W95 FAT32 (LBA)'.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

Now format the partitions:

mkfs.vfat /dev/sdx1
mkfs.ext4 /dev/sdx2

Simple & scripted version: TBW.

Prepare the rootfs

Please use root user in this section!

preparation

You need to install:

qemu-user-static
qemu-user-static-binfmt
arch-install-scripts

steps

Mount the partitions:

mount /dev/sdx2 /mnt
mkdir /mnt/boot
mount /dev/sdx1 /mnt/boot

Download the latest tarball: http://os.archlinuxarm.org/os/ArchLinuxARM-aarch64-latest.tar.gz

Extract as the root user (not via sudo) using bsdtar to preserve extended attributes and ACLs:

bsdtar -xpf ArchLinuxARM-aarch64-latest.tar.gz -C /mnt

Generate the fstab:

genfstab -U /mnt >> /mnt/etc/fstab

Note: inspect /mnt/etc/fstab to make sure no partitions on the host is included.

Copy the package linux-uconsole-cm3-rpi64(build it yourself with "/PKGBUILDs/linux-uconsole-cm3-rpi64") to the rootfs(/mnt)

Enter the rootfs with arch-chroot and install the packages:

arch-chroot /mnt
# initialize the keyring
pacman-key --init
pacman-key --populate archlinuxarm
# then install packages
pacman -Sy raspberrypi-bootloader firmware-raspberrypi
pacman -U --noconfirm linux-uconsole-cm3-rpi64*.pkg.zst

Note: preinstalled linux-aarch64 is uninstalled when installing linux-uconsole-cm3-rpi64.

Build and install the AUR package brcmfmac43456-firmware to have necessary WiFi firmware installed.

Now quit the rootfs.

Edit /mnt/boot/config.txt and write the following text:

[all]
ignore_lcd=1
disable_fw_kms_setup=1
disable_audio_dither
pwm_sample_bits=20

# setup headphone detect pin
gpio=10=ip,np

# boot custom kernel
kernel=Image.gz
arm_64bit=1
initramfs initramfs-linux.img followkernel

[all]
dtoverlay=dwc2,dr_mode=host
dtoverlay=audremap,pins_12_13
dtparam=audio=on

[pi3]
dtoverlay=vc4-kms-v3d
dtoverlay=uconsole

[cm4]
arm_boost=1
max_framebuffers=2
dtoverlay=vc4-kms-v3d-pi4
dtoverlay=uconsole,cm4,hwi2c

[cm4s]
arm_boost=1
max_framebuffers=2
dtoverlay=vc4-kms-v3d-pi4
dtoverlay=uconsole,hwi2c

[all]
# whatever you need

Note: The kernel command line can be changed by editing /mnt/boot/cmdline.txt.

Unmount the partitions:

umount /mnt/boot /mnt

You are ready to boot this SD card on uConsole.